I know very little about air conditioners. I do know that ours died today. The forced air blow but it is not cold. I also noticed that the compressor thingy with a big fan outside the house stopped turning. Instead, it is buzzings slightly and the motor is very warm. So, I suspect that the compressor is dead. Any recommendations on who to call to repair this? Or, is this an easy do-it-yourself project? Thanks!

My guess is the condenser fan motor has locked up and the buzzing you hear is the motor trying to turn. It will generate a lot of heat before the internal overloads open. Without the condenser fan the unit has no way to reject the heat from the refrigerant to the air and the compressor pressures will rise. If you have a high pressure switch it will open and the compressor will stop running to protect itself. Is the compressor still running and just the condenser fan motor stop? If thats the case the condenser fan motor has probably gone bad. You should stop running the AC until you fix the fan as you can potentially cause problems with the compressor. Couple of easy checks- With the power off see if the fan spins freely or if its locked up. If its locked up its bad. If it spins then check fuses/ breaker at the outdoor disconnect to make sure you have both legs of power. Check the run capacitor at the motor. I would say if you're not comfortable around electricity and confirming motors and compressors are good or bad you should probably call an reputable AC contractor. Don't waste your time or money replacing something only to find something else bad.